Originally Posted by
Kethmil
Fastest and surest way is doing invasions.
You get 2.500 shards on average on each. Two invasions is a 880+ piece on the slot you need it most.
Between invasions, do m+. Get your first key creating a group for regular mythic MoS on LFG. Then push it with LFG groups till it dies. Try to invite people on your gear type so they can pass you gear. The higher ilvl the pugs, the better since they'll carry you and will be more likely to pass you gear.
Then create your own bastion raid pugs. Put in the title something like "Fast run 900+ for AP and legens". You'll fill it up with 900+ people fast enough.
Keep in mind that a half-almost full group drags attention more than one with just person in it. You might have to invite lower ilvl people so it "seems fuller" and replace them later with higher ilvl people.